Press hardening is often used, inter alia, in automotive production, for example in conjunction with lightweight automotive concepts. It is often used there for deforming coated metallic components so that, on the one hand, the components do not undergo scaling during the heat treatment and, on the other hand, the durability of the tools is increased and corrosion protection for during subsequent use is ensured.
The components fed for press hardening are coated, for example, with an aluminum/silicon alloy. In the case of customary apparatuses, using such coatings often results, during the heat treatment in the furnace, in individual components of the furnace being adversely affected in thermochemical terms. Particularly affected here are parts of a transporting apparatus serving for conveying the components through the furnace and thus coming into direct contact with the components. This results in high costs for maintenance and servicing.
If the components which are to be deformed have a contact-sensitive coating, for example a zinc coating, contact for example with the transporting apparatus of the furnace may result in the coating being damaged. Contact of a zinc coating with some other, for example rough, surface, e.g. with rollers of a roller hearth furnace or with shelves of a chamber furnace, can be damaged as a result of the friction occurring here.
In the case of the known press-hardening methods, the components first of all are heated in the furnace to a temperature of, for example, approximately 950° C. and then are transported into a press. There, controlled cooling usually takes place during the shaping operation in the press. The furnace is designed usually in the form of a roller hearth furnace or of a chamber furnace, wherein, in the case of roller hearth furnaces, the components are guided through the furnace via a roller track and, in the case of a chamber furnace, the components are placed in the furnace by a manipulator. Other types of furnace, for example walking beam furnaces and chain furnaces, have not become generally accepted.
In order for the components to pass into the press with the lowest possible temperature loss, the components should be transferred as quickly as possible from the furnace into the press. This is carried out usually with the aid of a manipulator, such as a robot, which removes the components directly from the furnace or grips the components guided out through the furnace by a transporting apparatus, for example, the aforementioned roller track, and transfers said components into the press. The manipulator then also serves to move the component, prior to introduction into the press, into the correct position for example by rotation.
Both transportation between the furnace and press and the execution of the manipulations involve an amount of time which, for process-related reasons, is difficult to reduce, and, as a result, even before the shaping process has begun, the component cools or, in the case of uncoated components, is additionally subjected to scaling. Accordingly, the components have to be brought to a higher temperature in the furnace than would actually be necessary for the following shaping process in the press. This adversely affects the energy efficiency of the method. Furthermore, the operation of the components being transferred by the manipulator increases the risk of the coating being damaged by mechanical contact.
In the case of the known methods, therefore, a high degree of automation is necessary. The necessary manipulations mean that it is possible here not just for the coating to be damaged; rather, it is also the case that it is barely possible to reduce the cycle times, as is advantageous for efficient operation.
It is therefore an object of the invention to eliminate this disadvantage, and further disadvantages, of the prior art and to provide an apparatus for the press hardening of components which allows rapid, non-destructive, energy-efficient and cost-effective processing of the components. In particular the intention is to rule out as far as possible thermochemical attack of the coating of the components on means of a transporting apparatus and to avoid as far as possible the situation where the coating is damaged by contact. The components here should be transferred from the furnace into the press as quickly as possible, so that unnecessary cooling is prevented. It is also intended to provide a method for the press hardening of components using an apparatus according to the invention.
Configurations of the invention form the subject matter of claims 2 to 11.